Silver Decahedral Nanoparticles-Enhanced Fluorescence Resonance Energy Transfer Sensor for Specific Cell Imaging

We report on a silver decahedral nanoparticles (Ag(10)NPs)-based FRET (fluorescence resonance energy transfer) sensor for target cell imaging. Fluorophores-functionalized aptamers (Sgc8-FITC) were bound with Ag(10)NPs via the SH group on the aptamer to form Ag10-Sgc8-FITC. Then, quencher-carrying strands (BHQ-1) were hybridized with Sgc8-FITC to form a Ag(10)NPs-based FRET sensor (Ag10-Sgc8-F/Q). The sensor interacted with membrane protein tyrosine kinase-7 (PTK-7) on the CCRF-CEM (CCL-119, T-cell line, human acute lymphoblastic leukemia) cell surface to attain fluorescence imaging of CCRF-CEM cells. The addition of CCRF-CEM cells resulted in many sensors binding with cells membrane and the displacement of BHQ-1, thus disrupting the FRET effect and the enhanced fluorescence intensity of FITC. It was found that Ag(10)NPs largely enhanced the fluorescence intensity of FITC. The results also showed that the Ag(10)NPs-based FRET sensor (Ag10-Sgc8-F/Q) was not only superior to the bare FRET sensor (Sgc8-F/Q) and sensor Ag-Sgc8-F/Q but also highly sensitive and specific for CCRF-CEM cells imaging.